Light-emitting device

ABSTRACT

A light-emitting device includes a strip-like high flexibility region and a strip-like low flexibility region arranged alternately in a direction. The high flexibility region includes a flexible light-emitting panel. The low flexibility region includes the light-emitting panel and a support panel having a lower flexibility than that of the light-emitting panel and overlapping with the light-emitting panel. It is preferable that the light-emitting panel include an external connection electrode and that a length in the direction of a low flexibility region A that overlaps with the external connection electrode be longer than a length in the direction of a low flexibility region B that is closest to the region A.

TECHNICAL FIELD

The present invention relates to a light-emitting device, a displaydevice, an electronic device, a lighting device, or a manufacturingmethod thereof. In particular, the present invention relates to alight-emitting device, a display device, an electronic device, or alighting device utilizing electroluminescence (EL) or a manufacturingmethod thereof.

BACKGROUND ART

Recent light-emitting devices and display devices are expected to beapplied to a variety of uses and become diversified.

For example, light-emitting devices and display devices for mobiledevices and the like are required to be thin, lightweight, and lesslikely to be broken.

Light-emitting elements utilizing EL (also referred to as EL elements)have features such as ease of thinning and lightening, high-speedresponse to input signal, and driving with a direct-current low voltagesource; therefore, application of the light-emitting elements tolight-emitting devices and display devices has been proposed.

For example, Patent Document 1 discloses a flexible active matrixlight-emitting device in which an organic EL element and a transistorserving as a switching element are provided over a film substrate.

REFERENCE Patent Document

-   [Patent Document 1] Japanese Published Patent Application No.    2003-174153

DISCLOSURE OF INVENTION

For example, a display device that is reduced in size for highportability to have a small display region can display less informationon one screen and is less browsable.

An object of one embodiment of the present invention is to provide ahighly portable light-emitting device, display device, electronicdevice, or lighting device. Another object of one embodiment of thepresent invention is to provide a highly browsable light-emittingdevice, display device, or electronic device. Another object of oneembodiment of the present invention is to provide a highly portable andhighly browsable light-emitting device, display device, or electronicdevice.

An object of one embodiment of the present invention is to provide anovel light-emitting device, display device, electronic device, orlighting device. Another object of one embodiment of the presentinvention is to provide a lightweight light-emitting device, displaydevice, electronic device, or lighting device. Another object of oneembodiment of the present invention is to provide a highly reliablelight-emitting device, display device, electronic device, or lightingdevice. Another object of one embodiment of the present invention is toprovide a light-emitting device, display device, electronic device, orlighting device that is less likely to be broken. Another object of oneembodiment of the present invention is to provide a thin light-emittingdevice, display device, electronic device, or lighting device. Anotherobject of one embodiment of the present invention is to provide aflexible light-emitting device, display device, electronic device, orlighting device. Another object of one embodiment of the presentinvention is to provide a light-emitting device or lighting device witha seamless large light-emitting region or a display device or electronicdevice with a seamless large display region. Another object of oneembodiment of the present invention is to provide a light-emittingdevice, display device, electronic device, or lighting device with lowpower consumption.

In one embodiment of the present invention, there is no need to achieveall the objects.

A light-emitting device of one embodiment of the present inventionincludes a strip-like high flexibility region and a strip-like lowflexibility region that are arranged alternately. The light-emittingdevice can be folded by bending the high flexibility region. Alight-emitting device of one embodiment of the present invention ishighly portable in a folded state, and is highly browsable in an openedstate because of a seamless large light-emitting region. With oneembodiment of the present invention, the portability of a device can beincreased without a decrease in the size of a light-emitting region or adisplay region.

Specifically, one embodiment of the present invention is alight-emitting device including a flexible light-emitting panel and aplurality of support panels that are apart from each other and supportthe light-emitting panel. The support panel has a lower flexibility thanthat of the light-emitting panel.

One embodiment of the present invention is a light-emitting deviceincluding a strip-like high flexibility region and a strip-like lowflexibility region arranged alternately in a first direction. The highflexibility region includes a flexible light-emitting panel. The lowflexibility region includes the light-emitting panel and a support panelhaving a lower flexibility than that of the light-emitting panel andoverlapping with the light-emitting panel.

It is preferable that the above light-emitting device further include aprotective layer having a higher flexibility than that of the supportpanel, and that the high flexibility region and the low flexibilityregion include the light-emitting panel and the protective layeroverlapping with the light-emitting panel.

Another embodiment of the present invention is a light-emitting deviceincluding a strip-like high flexibility region and a strip-like lowflexibility region arranged alternately in a first direction. The highflexibility region includes a flexible light-emitting panel. The lowflexibility region includes a support panel having a lower flexibilitythan that of the light-emitting panel and the light-emitting panel heldby the support panel.

It is preferable that the above light-emitting device further include apair of protective layers and that the protective layer have a higherflexibility than that of the support panel. It is also preferable thatin the low flexibility region, the pair of protective layers be held bythe support panel and the light-emitting panel be placed between thepair of protective layers.

Another embodiment of the present invention is a light-emitting deviceincluding a strip-like high flexibility region and a strip-like lowflexibility region arranged alternately in a first direction. The highflexibility region includes a flexible light-emitting panel. The lowflexibility region includes a pair of support panels and thelight-emitting panel between the pair of support panels. The supportpanel has a lower flexibility than that of the light-emitting panel.

It is preferable that the above light-emitting device further include apair of protective layers and that the protective layer have a higherflexibility than that of the support panel. It is also preferable thatin the low flexibility region, the pair of protective layers be placedbetween the pair of support panels and the light-emitting panel beplaced between the pair of protective layers.

In any of the above light-emitting devices, it is preferable that whenone of two adjacent high flexibility regions is bent inward and theother is bent outward, a circle whose radius is a curvature radius ofthe light-emitting panel in the one high flexibility region and a circlewhose radius is a curvature radius of the light-emitting panel in theother high flexibility region overlap with each other by being moved ina direction parallel to a support plane of the light-emitting device.

Note that in this specification, being “bent inward” means being bentsuch that a light-emitting surface of a light-emitting panel facesinward, and being “bent outward” means being bent such that alight-emitting surface of a light-emitting panel faces outward. Alight-emitting surface of a light-emitting panel or a light-emittingdevice refers to a surface through which light emitted from alight-emitting element is extracted.

In any of the above light-emitting devices, it is preferable that when aplurality of high flexibility regions are bent inward and outwardalternately, the shortest distance L between a surface of thelight-emitting panel that is closest to a support plane of thelight-emitting device and a surface of the light-emitting panel that isfarthest from the support plane satisfy L<2(D+T). Here, D represents thesum of curvature radii of the light-emitting panel in the plurality ofhigh flexibility regions and T represents a thickness of thelight-emitting panel.

In any of the above light-emitting devices, it is preferable that thelight-emitting panel include an external connection electrode and that alength in the first direction of a low flexibility region A thatoverlaps with the external connection electrode be longer than a lengthin the first direction of a low flexibility region B that is closest tothe region A.

In the above light-emitting device, it is preferable that among theregion A, the region B, and a low flexibility region C that is farthestfrom the region A, a length in the first direction of the region A bethe longest and a length in the first direction of the region C be thesecond longest.

In the above light-emitting devices, it is preferable that among aplurality of low flexibility regions, a length in the first direction ofthe region A be the longest.

Embodiments of the present invention also include an electronic deviceincluding the above light-emitting device and a lighting deviceincluding the above light-emitting device. In addition, the abovelight-emitting device itself functions as an electronic device or alighting device in some cases.

Note that the light-emitting device in this specification includes, inits category, a display device using a light-emitting element. Further,the category of the light-emitting device in this specification includesa module in which a light-emitting element is provided with a connectorsuch as an anisotropic conductive film or a TCP (tape carrier package);a module having a TCP at the tip of which a printed wiring board isprovided; and a module in which an IC (integrated circuit) is directlymounted on a light-emitting element by a COG (chip on glass) method.Furthermore, the category includes a light-emitting device which is usedin lighting equipment or the like.

In one embodiment of the present invention, a highly portablelight-emitting device, display device, electronic device, or lightingdevice can be provided. In one embodiment of the present invention, ahighly browsable light-emitting device, display device, or electronicdevice can be provided. In one embodiment of the present invention, ahighly portable and highly browsable light-emitting device, displaydevice, or electronic device can be provided.

In one embodiment of the present invention, a novel light-emittingdevice, display device, electronic device, or lighting device can beprovided. In one embodiment of the present invention, a lightweightlight-emitting device, display device, electronic device, or lightingdevice can be provided. In one embodiment of the present invention, ahighly reliable light-emitting device, display device, electronicdevice, or lighting device can be provided. In one embodiment of thepresent invention, a light-emitting device, display device, electronicdevice, or lighting device that is less likely to be broken can beprovided. In one embodiment of the present invention, a thinlight-emitting device, display device, electronic device, or lightingdevice can be provided. In one embodiment of the present invention, aflexible light-emitting device, display device, electronic device, orlighting device can be provided. In one embodiment of the presentinvention, a light-emitting device or lighting device with a seamlesslarge light-emitting region or a display device or electronic devicewith a seamless large display region can be provided. In one embodimentof the present invention, a light-emitting device, display device,electronic device, or lighting device with low power consumption can beprovided.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C illustrate a light-emitting device.

FIG. 2 illustrates a light-emitting device.

FIGS. 3A to 3F illustrate light-emitting devices.

FIGS. 4A to 4D illustrate light-emitting devices.

FIGS. 5A to 5D illustrate light-emitting devices.

FIGS. 6A and 6B illustrate light-emitting devices.

FIGS. 7A and 7B illustrate a light-emitting panel.

FIGS. 8A and 8B each illustrate a light-emitting panel.

FIGS. 9A and 9B each illustrate a light-emitting panel.

FIGS. 10A and 10B each illustrate a light-emitting panel.

FIGS. 11A to 11C illustrate a method for manufacturing a light-emittingpanel.

FIGS. 12A to 12C illustrate a method for manufacturing a light-emittingpanel.

FIG. 13 illustrates a light-emitting panel.

FIGS. 14A to 14C illustrate a light-emitting device.

FIG. 15 illustrates a light-emitting device.

FIGS. 16A to 16F illustrate light-emitting devices.

FIGS. 17A and 17B illustrate light-emitting devices.

FIGS. 18A and 18B illustrate a light-emitting panel.

FIGS. 19A to 19D show a light-emitting device.

FIGS. 20A to 20C illustrate a light-emitting device.

FIGS. 21A to 21C illustrate alight-emitting device.

FIG. 22 illustrates a light-emitting device.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments will be described in detail with reference to drawings. Notethat the present invention is not limited to the description below, andit is easily understood by those skilled in the art that various changesand modifications can be made without departing from the spirit andscope of the present invention. Therefore, the present invention shouldnot be construed as being limited to the description in the followingembodiments.

Note that in the structures of the invention described below, the sameportions or portions having similar functions are denoted by the samereference numerals in different drawings, and description of suchportions is not repeated. Further, the same hatching pattern is appliedto portions having similar functions, and the portions are notespecially denoted by reference numerals in some cases.

In addition, the position, size, range, or the like of each structureillustrated in drawings and the like is not accurately represented insome cases for easy understanding. Therefore, the disclosed invention isnot necessarily limited to the position, the size, the range, or thelike disclosed in the drawings and the like.

Embodiment 1

In this embodiment, light-emitting devices of embodiments of the presentinvention will be described.

A light-emitting device of one embodiment of the present inventionincludes a strip-like high flexibility region and a strip-like lowflexibility region that are arranged alternately. The light-emittingdevice can be folded by bending the high flexibility region. Alight-emitting device of one embodiment of the present invention ishighly portable in a folded state, and is highly browsable in an openedstate because of a seamless large light-emitting region.

In the light-emitting device of one embodiment of the present invention,the high flexibility region can be bent either inward or outward.

When the light-emitting device of one embodiment of the presentinvention is not in use, it can be folded such that a light-emittingsurface of a light-emitting panel faces inward, whereby thelight-emitting surface can be prevented from being damaged orcontaminated.

When the light-emitting device of one embodiment of the presentinvention is in use, it can be opened so that the seamless largelight-emitting region is entirely used, or it can be folded such thatthe light-emitting surface of the light-emitting panel faces outward andthe light-emitting region can be partly used. Folding the light-emittingdevice and putting part of the light-emitting region that is hidden froma user in a non-light-emitting region can reduce the power consumptionof the light-emitting device.

A light-emitting device that can be folded in three parts and includestwo strip-like high flexibility regions and three strip-like lowflexibility regions is described below as an example.

FIG. 1A illustrates the light-emitting device that is opened. FIG. 1Billustrates the light-emitting device that is being opened or beingfolded. FIG. 1C illustrates the light-emitting device that is folded.FIG. 2 is a perspective view illustrating components of thelight-emitting device. FIG. 3A is a plan view of the light-emittingsurface side of the light-emitting device, and FIG. 3B is a plan view ofthe side opposite to the light-emitting surface side of thelight-emitting device. FIGS. 3C, 3D, and 3F are examples of a side viewof the light-emitting device in FIG. 3A that is viewed in the directionindicated by an arrow. FIG. 3E is a cross-sectional view taken alongdashed-dotted line A-B in FIG. 3A. FIGS. 4A, 4C, and 4D are examples ofa side view of the light-emitting device in FIG. 1C that is viewed inthe direction indicated by an arrow.

FIG. 14A, FIG. 14B, and FIG. 14C show variations of FIG. 1A, FIG. 1B,and

FIG. 1C, respectively. FIG. 14A illustrates the light-emitting devicethat is opened. FIG. 14B illustrates the light-emitting device that isbeing opened or being folded. FIG. 14C illustrates the light-emittingdevice that is folded. FIG. 15 is a perspective view illustratingcomponents of the light-emitting device. FIG. 16A is a plan view of thelight-emitting surface side of the light-emitting device, and FIG. 16Bis a plan view of the side opposite to the light-emitting surface sideof the light-emitting device. FIGS. 16C and 16D are examples of a sideview of the light-emitting device in FIG. 16A that is viewed in thedirection indicated by an arrow. FIG. 16E is a cross-sectional viewtaken along dashed-dotted line A-B in FIG. 16A. FIG. 16F shows avariation of the light-emitting device shown in FIG. 16C and the like.

The light-emitting device in FIGS. 1A to 1C and the light-emittingdevice in FIGS. 14A to 14C each include a flexible light-emitting panel11, a plurality of support panels 15 a, and a plurality of supportpanels 15 b. Each of the support panels 15 a and 15 b has a lowerflexibility than that of the light-emitting panel 11. The plurality ofsupport panels 15 a are apart from each other. The plurality of supportpanels 15 b are apart from each other.

As shown in FIG. 3A, the light-emitting device includes high flexibilityregions E1 and low flexibility regions E2 that are arranged alternately.The high flexibility region and the low flexibility region arestrip-like regions (form stripes). In this embodiment, a plurality ofhigh flexibility regions and a plurality of low flexibility regions areparallel to each other; however, the regions are not necessarilyarranged parallel to each other.

The high flexibility region E1 in the light-emitting device includes atleast a flexible light-emitting panel. A light-emitting panel usingorganic EL elements is particularly preferable because it not only hashigh flexibility and impact resistance but also can be thinned andlightened. Examples of a structure of a light-emitting panel aredetailed in Embodiments 2 and 3.

The low flexibility region E2 in the light-emitting device includes atleast a flexible light-emitting panel and a support panel having a lowerflexibility than that of the light-emitting panel and overlapping withthe light-emitting panel.

As shown in FIG. 16A, the light-emitting device includes a highflexibility region and a low flexibility region that are arrangedalternately in one direction.

In FIG. 16A, W1 to W3 represent the lengths of the low flexibilityregions in the direction in which the high flexibility region and thelow flexibility region are arranged.

In addition, the low flexibility region preferably includes an externalconnection electrode of the light-emitting panel. Here, the externalconnection electrode corresponds to, for example, a conductive layer 157in FIG. 7B.

In FIG. 16A, the low flexibility region with the length W1 includes theexternal connection electrode. In the light-emitting device, the lengthW1 of a low flexibility region A overlapping with the externalconnection electrode is longer than the length W3 of a low flexibilityregion B that is closer to the region A.

Here, when an end portion (also referred to as a folded portion or thelike) of the light-emitting panel 11 is positioned on the outer sidethan end portions of the support panels 15 a and 15 b in thelight-emitting device in a folded state, the light-emitting panel 11 isdamaged or an element included in the light-emitting panel 11 is brokenin some cases.

In the light-emitting device in a folded state shown in FIG. 1C, the endportion of the light-emitting panel 11 is aligned with the end portionsof the support panels 15 a and 15 b over and below the light-emittingpanel 11. This structure can prevent damage to the light-emitting panel11, breakage of an element included in the light-emitting panel 11, andthe like.

Moreover, in the light-emitting device in a folded state shown in FIG.14C, the end portion of the light-emitting panel 11 is positioned on theinner side than the end portions of the support panels 15 a and 15 b.This structure can further prevent damage to the light-emitting panel11, breakage of an element included in the light-emitting panel 11, andthe like.

Accordingly, in the light-emitting device, it is preferable that thelength W1 of the low flexibility region A overlapping with the externalconnection electrode be longer than the length W3 of the low flexibilityregion B that is closer to the region A. It is particularly preferablethat, among the length W1 of the region A, the length W3 of the regionB, and the length W2 of a low flexibility region C that is farther fromthe region A, W1 be the longest and W2 be the second longest.

The support panel is provided on at least one of the light-emittingsurface side and the side opposite to the light-emitting surface side ofthe light-emitting panel.

The light-emitting panel preferably has support panels on both thelight-emitting surface side and the side opposite to the light-emittingsurface side, like the support panels 15 a and 15 b shown in FIG. 3C orFIG. 16C, in which case the light-emitting panel can be sandwichedbetween a pair of support panels; thus, the mechanical strength of thelow flexibility region is increased and the light-emitting devicebecomes less likely to be broken.

Alternatively, a support panel 15 shown in FIG. 3D or FIG. 16D may beused instead of the support panels 15 a and 15 b and the light-emittingpanel 11 may be held by the support panel 15.

In FIG. 1A, FIG. 2, and FIG. 3C, for example, side surfaces of aprotective layer and the light-emitting panel are exposed in the lowflexibility region E2; however, one embodiment of the present inventionis not limited thereto. As shown in FIG. 3F, side surfaces of theprotective layer and the light-emitting panel may be covered with thesupport panel 15 (or one or both of the pair of support panels 15 a and15 b) in the low flexibility region E2. FIGS. 21A to 21C illustrate aspecific structure of a light-emitting device in which side surfaces ofthe protective layer and the light-emitting panel are covered with thesupport panel 15 b. FIG. 21A illustrates the light-emitting device thatis opened. FIG. 21B illustrates the light-emitting device that is beingopened or being folded. FIG. 21C illustrates the light-emitting devicethat is folded. FIG. 22 is a perspective view illustrating components ofthe light-emitting device.

It is preferable that the light-emitting panel have the support panel ononly one of the light-emitting surface side and the side opposite to thelight-emitting surface side because the light-emitting device can bethinner or more lightweight. For example, as shown in FIG. 16F, alight-emitting device that includes the plurality of support panels 15 band does not include the plurality of support panels 15 a may beemployed.

The high flexibility region E1 and the low flexibility region E2preferably include the light-emitting panel and a protective layerhaving a higher flexibility than that of the support panel andoverlapping with the light-emitting panel. In that case, the highflexibility region E1 in the light-emitting device can have highmechanical strength as well as flexibility and the light-emitting devicebecomes less likely to be broken. This structure makes thelight-emitting device less likely to be broken by deformation due toexternal force or the like in the high flexibility region as well as thelow flexibility region.

For example, it is preferable that the support panel be the thickest andthe light-emitting panel be the thinnest among the light-emitting panel,the support panel, and the protective layer. Alternatively, for example,it is preferable that the support panel have the lowest flexibility andthe light-emitting panel have the highest flexibility among thelight-emitting panel, the support panel, and the protective layer. Sucha structure increases the difference in flexibility between the highflexibility region and the low flexibility region. Thus, thelight-emitting device can be folded reliably at the high flexibilityregion, so that the low flexibility region is prevented from being bent.Consequently, the reliability of the light-emitting device can beimproved. Such a structure also prevents the light-emitting device frombeing bent at an undesired portion.

The light-emitting panel preferably has protective layers on both thelight-emitting surface side and the side opposite to the light-emittingsurface side, in which case the light-emitting panel can be sandwichedbetween a pair of protective layers; thus, the light-emitting device hasincreased mechanical strength and becomes less likely to be broken.

For example, as shown in FIG. 3C or FIG. 16C, in the low flexibilityregion E2, it is preferable that a pair of protective layers 13 a and 13b be placed between the pair of support panels 15 a and 15 b and thelight-emitting panel (not shown) be placed between the pair ofprotective layers 13 a and 13 b.

Alternatively, as shown in FIG. 3D or FIG. 16D, in the low flexibilityregion E2, it is preferable that the pair of protective layers 13 a and13 b be held by the support panel 15 and the light-emitting panel (notshown) be placed between the pair of protective layers 13 a and 13 b.

It is preferable that the light-emitting panel have the protective layeron only one of the light-emitting surface side and the side opposite tothe light-emitting surface side because the light-emitting device can bethinner or more lightweight. For example, a light-emitting device thatincludes the protective layer 13 b and does not include the protectivelayer 13 a may be employed.

When the protective layer 13 a on the light-emitting surface side of thelight-emitting panel is a light-blocking film, a non-light-emittingregion of the light-emitting panel can be prevented from beingirradiated with external light. This structure is preferable because itprevents photodegradation of a transistor and the like of a drivercircuit that is included in the non-light-emitting region.

As shown in FIG. 2, FIG. 3E, FIG. 15, or FIG. 16E, an opening in theprotective layer 13 a provided on the light-emitting surface side of thelight-emitting panel 11 overlaps with a light-emitting region 11 a ofthe light-emitting panel. The protective layer 13 a overlaps with anon-light-emitting region 11 b that surrounds the light-emitting region11 a like a frame. The protective layer 13 b provided on the sideopposite to the light-emitting surface side of the light-emitting panel11 overlaps with the light-emitting region 11 a and thenon-light-emitting region 11 b. The protective layer 13 b is provided ina large region, preferably on the entire surface on the side opposite tothe light-emitting surface side to strongly protect the light-emittingpanel; thus, the reliability of the light-emitting device can beimproved.

In the light-emitting device of one embodiment of the present invention,it is preferable that when a plurality of high flexibility regions arebent inward and outward alternately, the shortest distance L between asurface of the light-emitting panel that is closest to a support planeof the light-emitting device and a surface of the light-emitting panelthat is farthest from the support plane satisfy L<2(D+T). Here, Drepresents the sum of curvature radii of the light-emitting panel in theplurality of high flexibility regions and T represents a thickness ofthe light-emitting panel. In that case, the light-emitting device can bemade thinner.

The light-emitting device shown in FIG. 4A is in a state where one highflexibility region is bent inward and one high flexibility region isbent outward. The light-emitting panel is placed at the boundary betweenthe protective layer 13 a and the protective layer 13 b in FIG. 4A. Adiameter D1 and a diameter D2 in FIG. 4A are described in detail withreference to FIG. 4B. D1 represents a diameter of a circle whose radiusis the curvature radius of the light-emitting panel in the highflexibility region that is bent inward. D2 represents a diameter of acircle whose radius is the curvature radius of the light-emitting panelin the high flexibility region that is bent outward. T represents thethickness of the light-emitting panel 11. Since the sum of the diameterD1 and the diameter D2 corresponds to twice the sum D of the curvatureradii of the light-emitting panel in the plurality of high flexibilityregions, L<2(D+T) corresponds to L<D1+D2+2T. Here, the shortest distanceL1 between a surface that is closest to a support plane of thelight-emitting device and a surface that is farthest from the supportplane of the light-emitting panel in FIG. 4A is represented by D1+D2+3T.

By reducing the thicknesses of the support panels 15 a and 15 b or thethicknesses of the protective layers 13 a and 13 b or narrowing thewidth of the low flexibility region between the high flexibility regionthat is bent inward and the high flexibility region that is bentoutward, for example, the shortest distance L2 between a surface that isclosest to a support plane of the light-emitting device and a surfacethat is farthest from the support plane of the light-emitting panel inFIG. 4C can satisfy L2<D1+D2+3T or even satisfy L2<D1+D2+2T, i.e.,L2<2(D+T).

Here, in the light-emitting device, it is preferable that a pair of lowflexibility regions positioned on the outer side among the lowflexibility regions that are overlapped by folding the light-emittingdevice be parallel to the support plane of the light-emitting device,and that a low flexibility region positioned on the inner side not beparallel to the support plane.

In the light-emitting device of one embodiment of the present invention,it is preferable that when one of two adjacent high flexibility regionsis bent inward and the other is bent outward, a circle whose radius is acurvature radius of the light-emitting panel in the one high flexibilityregion and a circle whose radius is a curvature radius of thelight-emitting panel in the other high flexibility region overlap witheach other by being moved in a direction parallel to a support plane ofthe light-emitting device. In that case, the light-emitting device canbe made thinner.

As shown in FIG. 4D, a circle with the diameter D1 and a circle with thediameter D2 overlap with each other by being moved in a directionparallel to the support plane of the light-emitting device (here, in thehorizontal direction in the drawing). The curvature radius of thelight-emitting panel in the high flexibility region that is bent inwardand the curvature radius of the light-emitting panel in the highflexibility region that is bent outward correspond to the radii of thetwo circles; accordingly, it can be said that the light-emitting devicein FIG. 4D is thin.

The shortest distance L3 between a surface that is closest to a supportplane of the light-emitting device and a surface that is farthest fromthe support plane of the light-emitting panel in FIG. 4D can satisfyL3<D1+D2+3T or even satisfy L3<D1+D2+2T, i.e., L3<2(D+T). Note that inFIG. 4D, the protective layer 13 a and the protective layer 13 b arecollectively shown as a protective layer 13.

The protective layer and the support panel can be formed using plastic,a metal, an alloy, rubber, or the like. Plastic, rubber, or the like ispreferably used because it can form a protective layer or a supportpanel that is lightweight and less likely to be broken. For example,silicone rubber may be used for the protective layer and stainless steelor aluminum may be used for the support panel.

The protective layer and the support panel are preferably formed using amaterial with high toughness. In that case, a light-emitting device withhigh impact resistance that is less likely to be broken can be provided.For example, when an organic resin, a thin metal material, or a thinalloy material is used for the protective layer and the support panel,the light-emitting device can be lightweight and less likely to bebroken. For a similar reason, also a substrate of the light-emittingpanel is preferably formed using a material with high toughness.

The protective layer and the support panel on the light-emitting surfaceside do not necessarily have a light-transmitting property if they donot overlap with the light-emitting region of the light-emitting panel.When the protective layer and the support panel on the light-emittingsurface side overlap with at least part of the light-emitting region,they are preferably formed using a material that transmits light emittedfrom the light-emitting panel. There is no limitation on thelight-transmitting property of the protective layer and the supportpanel on the side opposite to the light-emitting surface side.

When any two of the protective layer, the support panel, and thelight-emitting panel are bonded to each other, any of a variety ofadhesives can be used, and for example, a curable resin that is curableat room temperature (e.g., a two-component-mixture-type resin), a lightcurable resin, a thermosetting resin, or the like can be used.Alternatively, a sheet-like adhesive may be used. Alternatively,components of the light-emitting device may be fixed with, for example,a screw that penetrates two or more of the protective layer, the supportpanel, and the light-emitting panel or a pin or clip that holds them.

The light-emitting device of one embodiment of the present invention canbe used with one light-emitting panel (one light-emitting region)divided into two or more regions at a folded portion(s). For example, itis possible to put the region that is hidden by folding thelight-emitting device in a non-light-emitting state and put only theexposed region in a light-emitting state. Thus, power consumed by aregion that is not used by a user can be reduced.

The light-emitting device of one embodiment of the present invention mayinclude a sensor for determining whether each high flexibility region isbent or not. The sensor can be composed of, for example, a switch, aMEMS pressure sensor, a pressure sensor, or the like.

In the examples described above, the light-emitting device includes twohigh flexibility regions; however, one embodiment of the presentinvention is not limited thereto. For example, as shown in FIG. 5A, thelight-emitting device includes at least one high flexibility region E1.Embodiments of the present invention also include a light-emittingdevice that includes three high flexibility regions E1 and can be foldedin four parts as shown in FIG. 5B or FIG. 17A and a light-emittingdevice that includes four high flexibility regions E1 and can be foldedin five parts as shown in FIG. 5C or FIG. 17B.

For example, in the light-emitting device shown in FIG. 17A, W1 is thelongest, W2 is the second longest, and W3 and W4 are the shortest amongthe lengths W1 to W4. The lengths W3 and W4 may be different lengths.

In addition, in the light-emitting device shown in FIG. 17B, W1 is thelongest, W2 is the second longest, and W3, W4, and W5 are the shortestamong the lengths W1 to W5. The lengths W3, W4, and W5 may be differentlengths.

FIGS. 6A and 6B each illustrate an example in which the light-emittingdevice in FIG. 5C is folded in five parts.

In FIG. 6A, the shortest distance L4 between a surface of thelight-emitting panel that is closest to a support plane of thelight-emitting device and a surface of the light-emitting panel that isfarthest from the support plane is represented by 2D+5T. Here, Drepresents the sum of the curvature radii of the light-emitting panel inthe plurality of high flexibility regions and T represents the thicknessof the light-emitting panel. Note that 2D=D1+D2+D3+D4.

By reducing the thicknesses of the support panels 15 a and 15 b or thethicknesses of the protective layers 13 a and 13 b or narrowing thewidth of the low flexibility region between the high flexibility regionthat is bent inward and the high flexibility region that is bentoutward, for example, the shortest distance L5 between a surface of thelight-emitting panel in FIG. 6B that is closest to a support plane ofthe light-emitting device and a surface of the light-emitting panel thatis farthest from the support plane can satisfy L5<D1+D2+D3+D4+5T, oreven satisfy L5<D1+D2+D3+D4+2T, i.e., L5<2D+2T. Here, D represents thesum of the curvature radii of the light-emitting panel in the pluralityof high flexibility regions and T represents the thickness of thelight-emitting panel.

In FIG. 6B, a circle with the diameter D1 and a circle with the diameterD2 overlap with each other by being moved in a direction parallel to thesupport plane of the light-emitting device (here, in the horizontaldirection in the drawing). In addition, a circle with the diameter D3and a circle with the diameter D4 overlap with each other by being movedin a direction parallel to the support plane of the light-emittingdevice. When one of the two adjacent high flexibility regions is bentinward and the other is bent outward, the radius of the circle with thediameter D1 and the radius of the circle with the diameter D2 correspondto the curvature radius of the light-emitting panel in the highflexibility region that is bent inward and the curvature radius of thelight-emitting panel in the high flexibility region that is bentoutward; accordingly, it can be said that the light-emitting device inFIG. 6B is thin. This can also be said from the radius of the circlewith the diameter D3 and the radius of the circle with the diameter D4.

Moreover, by reducing, as compared with a pair of low flexibilityregions on the outermost side of the light-emitting device, the widthsof the other low flexibility regions as shown in FIG. 6B, thelight-emitting device can be made even thinner.

Furthermore, when the light-emitting device is folded, the highflexibility regions are not necessarily bent inward and outwardalternately; for example, as shown in FIG. 5D, each high flexibilityregion may be bent inward. In such a state, when the light-emittingdevice is carried, for example, the light-emitting surface of thelight-emitting device can be prevented from being damaged orcontaminated.

In the light-emitting device of this embodiment, one light-emittingpanel can be folded once or more times. The curvature radius in thatcase can be, for example, greater than or equal to 1 mm and less than orequal to 150 mm.

This embodiment can be combined with any other embodiment asappropriate.

Embodiment 2

In this embodiment, light-emitting panels will be described withreference to FIGS. 7A and 7B, FIGS. 8A and 8B, FIGS. 9A and 9B, FIGS.10A and 10B, FIGS. 11A to 11C, and FIGS. 12A to 12C. When thelight-emitting panel described in this embodiment is bent, the minimumcurvature radius of a bent portion of the light-emitting panel can begreater than or equal to 1 mm and less than or equal to 150 mm, greaterthan or equal to 1 mm and less than or equal to 100 mm, greater than orequal to 1 mm and less than or equal to 50 mm, greater than or equal to1 mm and less than or equal to 10 mm, or greater than or equal to 2 mmand less than or equal to 5 mm. The light-emitting panel in thisembodiment is free from breakage of an element even when bent with asmall curvature radius (e.g., greater than or equal to 2 mm and lessthan or equal to 5 mm) and has high reliability. Bending thelight-emitting panel with a small curvature radius can make thelight-emitting device of one embodiment of the present invention thin.There is no limitation on the direction in which the light-emittingpanel in this embodiment is bent. Further, the number of bent portionsmay be one or more than one.

Specific Example 1

FIG. 7A is a plan view of the light-emitting panel 11 described as anexample in Embodiment 1, and FIG. 7B is an example of a cross-sectionalview taken along dashed-dotted line A1-A2 in FIG. 7A.

The light-emitting panel shown in FIG. 7B includes an element layer 101,a bonding layer 105, and a substrate 103. The element layer 101 includesa substrate 201, a bonding layer 203, an insulating layer 205, aplurality of transistors, the conductive layer 157, an insulating layer207, an insulating layer 209, a plurality of light-emitting elements, aninsulating layer 211, a sealing layer 213, an insulating layer 261, acoloring layer 259, a light-blocking layer 257, and an insulating layer255.

The conductive layer 157 is electrically connected to an FPC 108 via aconnector 215.

A light-emitting element 230 includes a lower electrode 231, an EL layer233, and an upper electrode 235. The lower electrode 231 is electricallyconnected to a source electrode or a drain electrode of a transistor240. An end portion of the lower electrode 231 is covered with theinsulating layer 211. The light-emitting element 230 has a top emissionstructure. The upper electrode 235 has a light-transmitting property andtransmits light emitted from the EL layer 233.

The coloring layer 259 is provided to overlap with the light-emittingelement 230, and the light-blocking layer 257 is provided to overlapwith the insulating layer 211. The coloring layer 259 and thelight-blocking layer 257 are covered with the insulating layer 261. Thespace between the light-emitting element 230 and the insulating layer261 is filled with the sealing layer 213.

The light-emitting panel includes a plurality of transistors includingthe transistor 240 in a light extraction portion 104 and a drivercircuit portion 106. The transistor 240 is provided over the insulatinglayer 205. The insulating layer 205 and the substrate 201 are attachedto each other with the bonding layer 203. The insulating layer 255 andthe substrate 103 are attached to each other with the bonding layer 105.It is preferable to use films with low water permeability for theinsulating layer 205 and the insulating layer 255, in which case animpurity such as water can be prevented from entering the light-emittingelement 230 or the transistor 240, leading to improved reliability ofthe light-emitting panel. The bonding layer 203 can be formed using amaterial similar to that of the bonding layer 105.

The light-emitting panel in Specific Example 1 can be manufactured inthe following manner: the insulating layer 205, the transistor 240, andthe light-emitting element 230 are formed over a formation substratewith high heat resistance; the formation substrate is separated; and theinsulating layer 205, the transistor 240, and the light-emitting element230 are transferred to the substrate 201 and attached thereto with thebonding layer 203. The light-emitting panel in Specific Example 1 can bemanufactured in the following manner: the insulating layer 255, thecoloring layer 259, and the light-blocking layer 257 are formed over aformation substrate with high heat resistance; the formation substrateis separated; and the insulating layer 255, the coloring layer 259, andthe light-blocking layer 257 are transferred to the substrate 103 andattached thereto with the bonding layer 105.

In the case where a material with low heat resistance (e.g., resin) isused for a substrate, it is difficult to expose the substrate to hightemperature in the manufacturing process. Thus, there is a limitation onconditions for forming a transistor and an insulating film over thesubstrate. Further, in the case where a material with high waterpermeability (e.g., resin) is used for a substrate of a light-emittingdevice, it is preferable to form a film with low water permeability athigh temperature between the substrate and a light-emitting element. Inthe manufacturing method of this embodiment, a transistor and the likecan be formed over a formation substrate having high heat resistance;thus, a highly reliable transistor and an insulating film withsufficiently low water permeability can be formed at high temperature.Then, the transistor and the insulating film are transferred to asubstrate with low heat resistance, whereby a highly reliablelight-emitting panel can be manufactured. Thus, with one embodiment ofthe present invention, a thin or/and lightweight light-emitting devicewith high reliability can be provided. Details of the manufacturingmethod will be described later.

The substrate 103 and the substrate 201 are each preferably formed usinga material with high toughness. In that case, a light-emitting panelwith high impact resistance that is less likely to be broken can beprovided. For example, when the substrate 103 is an organic resinsubstrate and the substrate 201 is a substrate formed using a thin metalmaterial or a thin alloy material, the light-emitting panel can belightweight and less likely to be broken as compared with the case wherea glass substrate is used.

A metal material and an alloy material, which have high thermalconductivity, are preferred because they can easily conduct heat to thewhole substrate and accordingly can prevent a local temperature rise inthe light-emitting panel. The thickness of a substrate using a metalmaterial or an alloy material is preferably greater than or equal to 10μm and less than or equal to 200 μm, further preferably greater than orequal to 20 μm and less than or equal to 50 μm.

Further, when a material with high thermal emissivity is used for thesubstrate 201, the surface temperature of the light-emitting panel canbe prevented from rising, leading to prevention of breakage or adecrease in reliability of the light-emitting panel. For example, thesubstrate 201 may have a stacked structure of a metal substrate and alayer with high thermal emissivity (the layer can be formed using ametal oxide or a ceramic material, for example).

Specific Example 2

FIG. 8A shows another example of the light extraction portion 104 in thelight-emitting panel. The light-emitting panel shown in FIG. 8A iscapable of touch operation. In the following specific examples,description of components similar to those in Specific Example 1 isomitted.

The light-emitting panel shown in FIG. 8A includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, the insulating layer 207, theinsulating layer 209, a plurality of light-emitting elements, theinsulating layer 211, an insulating layer 217, the sealing layer 213,the insulating layer 261, the coloring layer 259, the light-blockinglayer 257, a plurality of light-receiving elements, a conductive layer281, a conductive layer 283, an insulating layer 291, an insulatinglayer 293, an insulating layer 295, and the insulating layer 255.

Specific Example 2 includes the insulating layer 217 over the insulatinglayer 211. The space between the substrate 103 and the substrate 201 canbe adjusted with the insulating layer 217.

FIG. 8A shows an example in which a light-receiving element is providedbetween the insulating layer 255 and the sealing layer 213. Since thelight-receiving element can be placed to overlap with anon-light-emitting region (e.g., a region where the light-emittingelement is not provided, such as a region where a transistor or a wiringis provided) of the light-emitting panel, the light-emitting panel canbe provided with a touch sensor without a decrease in the aperture ratioof a pixel (light-emitting element).

As the light-receiving element included in the light-emitting panel, forexample, a PN photodiode or a PIN photodiode can be used. In thisembodiment, a PIN photodiode including a p-type semiconductor layer 271,an i-type semiconductor layer 273, and an n-type semiconductor layer 275is used as the light-receiving element.

Note that the i-type semiconductor layer 273 is a semiconductor in whichthe concentration of each of an impurity imparting p-type conductivityand an impurity imparting n-type conductivity is 1×10²⁰ cm⁻³ or less andwhich has photoconductivity 100 times or more as high as darkconductivity. The i-type semiconductor layer 273 also includes, in itscategory, a semiconductor that contains an impurity element belonging toGroup 13 or Group 15 of the periodic table. In other words, since ani-type semiconductor has weak n-type electric conductivity when animpurity element for controlling valence electrons is not addedintentionally, the i-type semiconductor layer 273 includes, in itscategory, a semiconductor to which an impurity element imparting p-typeconductivity is added intentionally or unintentionally at the time ofdeposition or after the deposition.

The light-blocking layer 257 is closer to the substrate 201 than is thelight-receiving element and overlaps with the light-receiving element.The light-blocking layer 257 between the light-receiving element and thesealing layer 213 can prevent the light-receiving element from beingirradiated with light emitted from the light-emitting element 230.

The conductive layer 281 and the conductive layer 283 are electricallyconnected to the light-receiving element. The conductive layer 281preferably transmits light incident on the light-receiving element. Theconductive layer 283 preferably blocks light incident on thelight-receiving element.

It is preferable to provide an optical touch sensor between thesubstrate 103 and the sealing layer 213 because the optical touch sensoris less likely to be affected by light emitted from the light-emittingelement 230 and can have improved S/N ratio.

Specific Example 3

FIG. 8B shows another example of the light extraction portion 104 in thelight-emitting panel. The light-emitting panel shown in FIG. 8B iscapable of touch operation.

The light-emitting panel shown in FIG. 8B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, the insulating layer 207, an insulatinglayer 209 a, an insulating layer 209 b, a plurality of light-emittingelements, the insulating layer 211, the insulating layer 217, thesealing layer 213, the coloring layer 259, the light-blocking layer 257,a plurality of light-receiving elements, a conductive layer 280, theconductive layer 281, and the insulating layer 255.

FIG. 8B shows an example in which a light-receiving element is providedbetween the insulating layer 205 and the sealing layer 213. Since thelight-receiving element is provided between the insulating layer 205 andthe sealing layer 213, a conductive layer to which the light-receivingelement is electrically connected and a photoelectric conversion layerincluded in the light-receiving element can be formed using the samematerials and the same steps as a conductive layer and a semiconductorlayer included in the transistor 240. Thus, the light-emitting panelcapable of touch operation can be manufactured without a significantincrease in the number of manufacturing steps.

Specific Example 4

FIG. 9A shows another example of a light-emitting panel. Thelight-emitting panel shown in FIG. 9A is capable of touch operation.

The light-emitting panel shown in FIG. 9A includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, a conductive layer 156, the conductivelayer 157, the insulating layer 207, the insulating layer 209, aplurality of light-emitting elements, the insulating layer 211, theinsulating layer 217, the sealing layer 213, the coloring layer 259, thelight-blocking layer 257, the insulating layer 255, a conductive layer272, a conductive layer 274, an insulating layer 276, an insulatinglayer 278, a conductive layer 294, and a conductive layer 296.

FIG. 9A shows an example in which a capacitive touch sensor is providedbetween the insulating layer 255 and the sealing layer 213. Thecapacitive touch sensor includes the conductive layer 272 and theconductive layer 274.

The conductive layer 156 and the conductive layer 157 are electricallyconnected to the FPC 108 via the connector 215. The conductive layer 294and the conductive layer 296 are electrically connected to theconductive layer 274 via conductive particles 292. Thus, the capacitivetouch sensor can be driven via the FPC 108.

Specific Example 5

FIG. 9B shows another example of a light-emitting panel. Thelight-emitting panel shown in FIG. 9B is capable of touch operation.

The light-emitting panel shown in FIG. 9B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, the conductive layer 156, theconductive layer 157, the insulating layer 207, the insulating layer209, a plurality of light-emitting elements, the insulating layer 211,the insulating layer 217, the sealing layer 213, the coloring layer 259,the light-blocking layer 257, the insulating layer 255, a conductivelayer 270, the conductive layer 272, the conductive layer 274, theinsulating layer 276, and the insulating layer 278.

FIG. 9B shows an example in which a capacitive touch sensor is providedbetween the insulating layer 255 and the sealing layer 213. Thecapacitive touch sensor includes the conductive layer 272 and theconductive layer 274.

The conductive layer 156 and the conductive layer 157 are electricallyconnected to an FPC 108 a via a connector 215 a. The conductive layer270 is electrically connected to an FPC 108 b via a connector 215 b.Thus, the light-emitting element 230 and the transistor 240 can bedriven via the FPC 108 a, and the capacitive touch sensor can be drivenvia the FPC 108 b.

Specific Example 6

FIG. 10A shows another example of the light extraction portion 104 inthe light-emitting panel.

The light-emitting panel shown in FIG. 10A includes the element layer101, the substrate 103, and the bonding layer 105. The element layer 101includes a substrate 202, the insulating layer 205, a plurality oftransistors, the insulating layer 207, a conductive layer 208, theinsulating layer 209 a, the insulating layer 209 b, a plurality oflight-emitting elements, the insulating layer 211, the sealing layer213, and the coloring layer 259.

The light-emitting element 230 includes the lower electrode 231, the ELlayer 233, and the upper electrode 235. The lower electrode 231 iselectrically connected to the source electrode or the drain electrode ofthe transistor 240 via the conductive layer 208. An end portion of thelower electrode 231 is covered with the insulating layer 211. Thelight-emitting element 230 has a bottom emission structure. The lowerelectrode 231 has a light-transmitting property and transmits lightemitted from the EL layer 233.

The coloring layer 259 is provided to overlap with the light-emittingelement 230, and light emitted from the light-emitting element 230 isextracted from the substrate 103 side through the coloring layer 259.The space between the light-emitting element 230 and the substrate 202is filled with the sealing layer 213. The substrate 202 can be formedusing a material similar to that of the substrate 201.

Specific Example 7

FIG. 10B shows another example of a light-emitting panel.

The light-emitting panel shown in FIG. 10B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 202, the insulating layer 205, a conductive layer310 a, a conductive layer 310 b, a plurality of light-emitting elements,the insulating layer 211, a conductive layer 212, and the sealing layer213.

The conductive layer 310 a and the conductive layer 310 b, which areexternal connection electrodes of the light-emitting panel, can each beelectrically connected to an FPC or the like.

The light-emitting element 230 includes the lower electrode 231, the ELlayer 233, and the upper electrode 235. An end portion of the lowerelectrode 231 is covered with the insulating layer 211. Thelight-emitting element 230 has a bottom emission structure. The lowerelectrode 231 has a light-transmitting property and transmits lightemitted from the EL layer 233. The conductive layer 212 is electricallyconnected to the lower electrode 231.

The substrate 103 may have, as a light extraction structure, ahemispherical lens, a micro lens array, a film provided with an unevensurface structure, a light diffusing film, or the like. For example, thesubstrate 103 with a light extraction structure can be formed byattaching the above lens or film to a resin substrate with an adhesiveor the like having substantially the same refractive index as thesubstrate or the lens or film.

The conductive layer 212 is preferably, though not necessarily, providedbecause voltage drop due to the resistance of the lower electrode 231can be prevented. In addition, for a similar purpose, a conductive layerelectrically connected to the upper electrode 235 may be provided overthe insulating layer 211, the EL layer 233, the upper electrode 235, orthe like.

The conductive layer 212 can be a single layer or a stacked layer formedusing a material selected from copper, titanium, tantalum, tungsten,molybdenum, chromium, neodymium, scandium, nickel, or aluminum, an alloymaterial containing any of these materials as its main component, or thelike. The thickness of the conductive layer 212 can be, for example,greater than or equal to 0.1 μm and less than or equal to 3 μm,preferably greater than or equal to 0.1 μm and less than or equal to 0.5μm.

When a paste (e.g., silver paste) is used as a material for theconductive layer electrically connected to the upper electrode 235,metal particles forming the conductive layer aggregate; therefore, thesurface of the conductive layer is rough and has many gaps. Thus, evenwhen the conductive layer is formed over the insulating layer 211, forexample, it is difficult for the EL layer 233 to completely cover theconductive layer; accordingly, the upper electrode and the conductivelayer are electrically connected to each other easily, which ispreferable.

Examples of Materials

Next, materials and the like that can be used for a light-emitting panelare described. Note that description on the components already describedin this embodiment is omitted.

The element layer 101 includes at least a light-emitting element. As thelight-emitting element, a self-luminous element can be used, and anelement whose luminance is controlled by current or voltage is includedin the category of the light-emitting element. For example, alight-emitting diode (LED), an organic EL element, an inorganic ELelement, or the like can be used.

The element layer 101 may further include a transistor for driving thelight-emitting element, a touch sensor, or the like.

The structure of the transistors in the light-emitting panel is notparticularly limited. For example, a forward staggered transistor or aninverted staggered transistor may be used. A top-gate transistor or abottom-gate transistor may be used. A semiconductor material used forthe transistors is not particularly limited, and for example, silicon orgermanium can be used. Alternatively, an oxide semiconductor containingat least one of indium, gallium, and zinc, such as an In—Ga—Zn-basedmetal oxide, may be used.

There is no particular limitation on the crystallinity of asemiconductor material used for the transistors, and an amorphoussemiconductor or a semiconductor having crystallinity (amicrocrystalline semiconductor, a polycrystalline semiconductor, asingle-crystal semiconductor, or a semiconductor partly includingcrystal regions) may be used. It is preferable that a semiconductorhaving crystallinity be used, in which case deterioration of thetransistor characteristics can be suppressed.

The light-emitting element included in the light-emitting panel includesa pair of electrodes (the lower electrode 231 and the upper electrode235); and the EL layer 233 between the pair of electrodes. One of thepair of electrodes functions as an anode and the other functions as acathode.

The light-emitting element may have any of a top emission structure, abottom emission structure, and a dual emission structure. A conductivefilm that transmits visible light is used as the electrode through whichlight is extracted. A conductive film that reflects visible light ispreferably used as the electrode through which light is not extracted.

The conductive film that transmits visible light can be formed using,for example, indium oxide, indium tin oxide (ITO), indium zinc oxide,zinc oxide, or zinc oxide to which gallium is added. Alternatively, afilm of a metal material such as gold, silver, platinum, magnesium,nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium,or titanium; an alloy containing any of these metal materials; or anitride of any of these metal materials (e.g., titanium nitride) can beformed thin so as to have a light-transmitting property. Alternatively,a stacked film of any of the above materials can be used as theconductive film. For example, a stacked film of ITO and an alloy ofsilver and magnesium is preferably used, in which case conductivity canbe increased. Further alternatively, graphene or the like may be used.

For the conductive film that reflects visible light, for example, ametal material such as aluminum, gold, platinum, silver, nickel,tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium or analloy containing any of these metal materials can be used. Further,lanthanum, neodymium, germanium, or the like may be added to the metalmaterial or the alloy. Furthermore, an alloy containing aluminum (analuminum alloy) such as an alloy of aluminum and titanium, an alloy ofaluminum and nickel, or an alloy of aluminum and neodymium; or an alloycontaining silver such as an alloy of silver and copper, an alloy ofsilver, copper, and palladium, or an alloy of silver and magnesium canbe used for the conductive film. An alloy of silver and copper ispreferable because of its high heat resistance. Further, when a metalfilm or a metal oxide film is stacked on and in contact with an aluminumalloy film, oxidation of the aluminum alloy film can be prevented.Examples of a material for the metal film or the metal oxide film aretitanium and titanium oxide. Alternatively, the above conductive filmthat transmits visible light and a film containing a metal material maybe stacked. For example, a stacked film of silver and ITO or a stackedfilm of an alloy of silver and magnesium and ITO can be used.

Each of the electrodes can be formed by an evaporation method or asputtering method. Alternatively, a discharging method such as an inkjetmethod, a printing method such as a screen printing method, or a platingmethod may be used.

When a voltage higher than the threshold voltage of the light-emittingelement is applied between the lower electrode 231 and the upperelectrode 235, holes are injected to the EL layer 233 from the anodeside and electrons are injected to the EL layer 233 from the cathodeside. The injected electrons and holes are recombined in the EL layer233 and a light-emitting substance contained in the EL layer 233 emitslight.

The EL layer 233 includes at least a light-emitting layer. In additionto the light-emitting layer, the EL layer 233 may further include one ormore layers containing any of a substance with a high hole-injectionproperty, a substance with a high hole-transport property, ahole-blocking material, a substance with a high electron-transportproperty, a substance with a high electron-injection property, asubstance with a bipolar property (a substance with a high electron- andhole-transport property), and the like.

For the EL layer 233, either a low molecular compound or a highmolecular compound can be used, and an inorganic compound may also beused. Each of the layers included in the EL layer 233 can be formed byany of the following methods: an evaporation method (including a vacuumevaporation method), a transfer method, a printing method, an inkjetmethod, a coating method, and the like.

In the element layer 101, the light-emitting element is preferablyprovided between a pair of insulating films with low water permeability.In that case, an impurity such as water can be prevented from enteringthe light-emitting element, leading to prevention of a decrease in thereliability of the light-emitting device.

As an insulating film with low water permeability, a film containingnitrogen and silicon (e.g., a silicon nitride film or a silicon nitrideoxide film), a film containing nitrogen and aluminum (e.g., an aluminumnitride film), or the like can be used. Alternatively, a silicon oxidefilm, a silicon oxynitride film, an aluminum oxide film, or the like canbe used.

For example, the water vapor transmittance of the insulating film withlow water permeability is lower than or equal to 1×10⁻⁵ [g/m²·day],preferably lower than or equal to 1×10⁻⁶ [g/m²·day], further preferablylower than or equal to 1×10⁻⁷ [g/m²·day], still further preferably lowerthan or equal to 1×10⁻⁸ [g/m²·day].

The substrate 103 has a light-transmitting property and transmits atleast light emitted from the light-emitting element included in theelement layer 101. The substrate 103 may be a flexible substrate. Therefractive index of the substrate 103 is higher than that of the air.

An organic resin, which is lighter than glass, is preferably used forthe substrate 103, in which case the light-emitting device can belightweight as compared with the case where glass is used.

Examples of a material having flexibility and a light-transmittingproperty with respect to visible light include glass that is thin enoughto have flexibility, polyester resins such as polyethylene terephthalate(PET) and polyethylene naphthalate (PEN), a polyacrylonitrile resin, apolyimide resin, a polymethyl methacrylate resin, a polycarbonate (PC)resin, a polyethersulfone (PES) resin, a polyamide resin, a cycloolefinresin, a polystyrene resin, a polyamide imide resin, and a polyvinylchloride resin. In particular, a material whose thermal expansioncoefficient is low is preferred, and for example, a polyamide imideresin, a polyimide resin, or PET can be suitably used. A substrate inwhich a glass fiber is impregnated with an organic resin or a substratewhose thermal expansion coefficient is reduced by mixing an organicresin with an inorganic filler can also be used.

The substrate 103 may have a stacked structure of a layer of any of theabove-mentioned materials and a hard coat layer (e.g., a silicon nitridelayer) which protects a surface of the light-emitting device from damageor the like, a layer (e.g., an aramid resin layer) which can dispersepressure, or the like. Furthermore, to suppress a decrease in thelifetime of the light-emitting element due to moisture and the like, theinsulating film with low water permeability may be included in thestacked structure.

The bonding layer 105 has a light-transmitting property and transmits atleast light emitted from the light-emitting element included in theelement layer 101. The refractive index of the bonding layer 105 ishigher than that of the air.

For the bonding layer 105, a curable resin that is curable at roomtemperature (e.g., a two-component-mixture-type resin), a light curableresin, a thermosetting resin, or the like can be used. Examples of suchresins include an epoxy resin, an acrylic resin, a silicone resin, and aphenol resin. In particular, a material with low moisture permeability,such as an epoxy resin, is preferred.

Further, the resin may include a drying agent. For example, a substancethat adsorbs moisture by chemical adsorption, such as oxide of analkaline earth metal (e.g., calcium oxide or barium oxide), can be used.Alternatively, a substance that adsorbs moisture by physical adsorption,such as zeolite or silica gel, may be used. The drying agent ispreferably included because it can prevent an impurity such as moisturefrom entering the light-emitting element, thereby improving thereliability of the light-emitting device.

In addition, it is preferable to mix a filler with a high refractiveindex (e.g., titanium oxide) into the resin, in which case theefficiency of light extraction from the light-emitting element can beimproved.

The bonding layer 105 may also include a scattering member forscattering light. For example, the bonding layer 105 can be a mixture ofthe above resin and particles having a refractive index different fromthat of the resin. The particles function as the scattering member forscattering light.

The difference in refractive index between the resin and the particleswith a refractive index different from that of the resin is preferably0.1 or more, further preferably 0.3 or more. Specifically, an epoxyresin, an acrylic resin, an imide resin, silicone, or the like can beused as the resin, and titanium oxide, barium oxide, zeolite, or thelike can be used as the particles.

Particles of titanium oxide or barium oxide are preferable because theyscatter light excellently. When zeolite is used, it can adsorb watercontained in the resin and the like, thereby improving the reliabilityof the light-emitting element.

The insulating layer 205 and the insulating layer 255 can each be formedusing an inorganic insulating material. It is particularly preferable touse the insulating film with low water permeability, in which case ahighly reliable light-emitting panel can be provided.

The insulating layer 207 has an effect of preventing diffusion ofimpurities into a semiconductor included in the transistor. As theinsulating layer 207, an inorganic insulating film such as a siliconoxide film, a silicon oxynitride film, a silicon nitride film, a siliconnitride oxide film, or an aluminum oxide film can be used.

As each of the insulating layers 209, 209 a, and 209 b, an insulatingfilm with a planarization function is preferably selected in order toreduce surface unevenness due to the transistor or the like. Forexample, an organic material such as a polyimide resin, an acrylicresin, or a benzocyclobutene-based resin can be used. Other than suchorganic materials, it is also possible to use a low-dielectric constantmaterial (a low-k material) or the like. Note that the planarizationinsulating film may have a stacked structure of any of insulating filmsformed of these materials and inorganic insulating films.

The insulating layer 211 is provided to cover an end portion of thelower electrode 231. In order that the insulating layer 211 be favorablycovered with the EL layer 233 and the upper electrode 235 formedthereover, a side wall of the insulating layer 211 preferably has atilted surface with continuous curvature.

As a material for the insulating layer 211, a resin or an inorganicinsulating material can be used. As the resin, for example, a polyimideresin, a polyamide resin, an acrylic resin, a siloxane resin, an epoxyresin, or a phenol resin can be used. In particular, either a negativephotosensitive resin or a positive photosensitive resin is preferablyused for easy formation of the insulating layer 211.

There is no particular limitation on the method for forming theinsulating layer 211; a photolithography method, a sputtering method, anevaporation method, a droplet discharging method (e.g., an inkjetmethod), a printing method (e.g., a screen printing method or an off-setprinting method), or the like may be used.

The insulating layer 217 can be formed using an inorganic insulatingmaterial, an organic insulating material, or the like. As the organicinsulating material, for example, a negative or positive photosensitiveresin, a non-photosensitive resin, or the like can be used. Instead ofthe insulating layer 217, a conductive layer may be formed. For example,the conductive layer can be formed using a metal material such astitanium or aluminum. When a conductive layer is used instead of theinsulating layer 217 and the conductive layer is electrically connectedto the upper electrode 235, voltage drop due to the resistance of theupper electrode 235 can be prevented. The insulating layer 217 may haveeither a tapered shape or an inverse tapered shape.

Each of the insulating layers 276, 278, 291, 293, and 295 can be formedusing an inorganic insulating material or an organic insulatingmaterial. It is particularly preferable to use an insulating film with aplanarization function for each of the insulating layers 278 and 295 inorder to reduce surface unevenness due to a sensor element.

For the sealing layer 213, a resin that is curable at room temperature(e.g., a two-component-mixture-type resin), a light curable resin, athermosetting resin, or the like can be used. For example, a polyvinylchloride (PVC) resin, an acrylic resin, a polyimide resin, an epoxyresin, a silicone resin, a polyvinyl butyral (PVB) resin, an ethylenevinyl acetate (EVA) resin, or the like can be used. A drying agent maybe contained in the sealing layer 213. In the case where light emittedfrom the light-emitting element 230 is extracted outside through thesealing layer 213, the sealing layer 213 preferably includes a fillerwith a high refractive index or a scattering member. Materials for thedrying agent, the filler with a high refractive index, and thescattering member are similar to those that can be used for the bondinglayer 105.

Each of the conductive layers 156, 157, 294, and 296 can be formed usingthe same material and the same step as a conductive layer included inthe transistor or the light-emitting element. The conductive layer 280can be formed using the same material and the same step as a conductivelayer included in the transistor.

For example, each of the conductive layers can be formed to have asingle-layer structure or a stacked-layer structure using any of metalmaterials such as molybdenum, titanium, chromium, tantalum, tungsten,aluminum, copper, neodymium, and scandium, and an alloy materialcontaining any of these elements. Each of the conductive layers may beformed using a conductive metal oxide. As the conductive metal oxide,indium oxide (e.g., In₂O₃), tin oxide (e.g., SnO₂), zinc oxide (ZnO),ITO, indium zinc oxide (e.g., In₂O₃—ZnO), or any of these metal oxidematerials in which silicon oxide is contained can be used.

Each of the conductive layers 208, 212, 310 a, and 310 b can also beformed using any of the above metal materials, alloy materials, andconductive metal oxides.

Each of the conductive layers 272, 274, 281, and 283 is a conductivelayer with a light-transmitting property. The conductive layer can beformed using, for example, indium oxide, ITO, indium zinc oxide, zincoxide, zinc oxide to which gallium is added, or the like. The conductivelayer 270 can be formed using the same material and the same step as theconductive layer 272.

As the conductive particles 292, particles of an organic resin, silica,or the like coated with a metal material are used. It is preferable touse nickel or gold as the metal material because contact resistance canbe reduced. It is also preferable to use particles each coated withlayers of two or more kinds of metal materials, such as particles coatedwith nickel and further with gold.

For the connector 215, it is possible to use a paste-like or sheet-likematerial which is obtained by mixture of metal particles and athermosetting resin and for which anisotropic electric conductivity isprovided by thermocompression bonding. As the metal particles, particlesin which two or more kinds of metals are layered, for example, nickelparticles coated with gold are preferably used.

The coloring layer 259 is a colored layer that transmits light in aspecific wavelength range. For example, a red (R) color filter fortransmitting light in a red wavelength range, a green (G) color filterfor transmitting light in a green wavelength range, a blue (B) colorfilter for transmitting light in a blue wavelength range, or the likecan be used. Each coloring layer is formed in a desired position withany of various materials by a printing method, an inkjet method, anetching method using a photolithography method, or the like.

The light-blocking layer 257 is provided between the adjacent coloringlayers 259. The light-blocking layer 257 blocks light emitted from theadjacent light-emitting element, thereby preventing color mixturebetween adjacent pixels. Here, the coloring layer 259 is provided suchthat its end portion overlaps with the light-blocking layer 257, wherebylight leakage can be reduced. The light-blocking layer 257 can be formedusing a material that blocks light emitted from the light-emittingelement, for example, a metal material, a resin material including apigment or a dye, or the like. Note that the light-blocking layer 257 ispreferably provided in a region other than the light extraction portion104, such as the driver circuit portion 106, as illustrated in FIG. 7B,in which case undesired leakage of guided light or the like can beprevented.

The insulating layer 261 covering the coloring layer 259 and thelight-blocking layer 257 is preferably provided because it can preventan impurity such as a pigment included in the coloring layer 259 or thelight-blocking layer 257 from diffusing into the light-emitting elementor the like. For the insulating layer 261, a light-transmitting materialis used, and an inorganic insulating material or an organic insulatingmaterial can be used. The insulating film with low water permeabilitymay be used for the insulating layer 261. Note that the insulating layer261 is not necessarily provided.

Example of Manufacturing Method

Next, an example of a method for manufacturing a light-emitting panelwill be described with reference to FIGS. 11A to 11C and FIGS. 12A to12C. Here, the manufacturing method is described using thelight-emitting panel of Specific Example 1 (FIG. 7B) as an example.

First, a separation layer 303 is formed over a formation substrate 301,and the insulating layer 205 is formed over the separation layer 303.Next, the plurality of transistors, the conductive layer 157, theinsulating layer 207, the insulating layer 209, the plurality oflight-emitting elements, and the insulating layer 211 are formed overthe insulating layer 205. An opening is formed in the insulating layers211, 209, and 207 to expose the conductive layer 157 (FIG. 11A).

In addition, a separation layer 307 is formed over a formation substrate305, and the insulating layer 255 is formed over the separation layer307. Next, the light-blocking layer 257, the coloring layer 259, and theinsulating layer 261 are formed over the insulating layer 255 (FIG.11B).

The formation substrate 301 and the formation substrate 305 can each bea glass substrate, a quartz substrate, a sapphire substrate, a ceramicsubstrate, a metal substrate, or the like.

For the glass substrate, for example, a glass material such asaluminosilicate glass, aluminoborosilicate glass, or barium borosilicateglass can be used. When the temperature of heat treatment performedlater is high, a substrate having a strain point of 730° C. or higher ispreferably used. Note that when containing a large amount of bariumoxide (BaO), the glass substrate can be heat-resistant and morepractical. Alternatively, crystallized glass or the like may be used.

In the case where a glass substrate is used as the formation substrate,an insulating film such as a silicon oxide film, a silicon oxynitridefilm, a silicon nitride film, or a silicon nitride oxide film ispreferably formed between the formation substrate and the separationlayer, in which case contamination from the glass substrate can beprevented.

The separation layer 303 and the separation layer 307 each have asingle-layer structure or a stacked-layer structure containing anelement selected from tungsten, molybdenum, titanium, tantalum, niobium,nickel, cobalt, zirconium, zinc, ruthenium, rhodium, palladium, osmium,iridium, and silicon; an alloy material containing any of the elements;or a compound material containing any of the elements. A crystalstructure of a layer containing silicon may be amorphous, microcrystal,or polycrystal.

The separation layer can be formed by a sputtering method, a plasma CVDmethod, a coating method, a printing method, or the like. Note that acoating method includes a spin coating method, a droplet dischargemethod, and a dispensing method.

In the case where the separation layer has a single-layer structure, atungsten layer, a molybdenum layer, or a layer containing a mixture oftungsten and molybdenum is preferably formed. Alternatively, a layercontaining an oxide or an oxynitride of tungsten, a layer containing anoxide or an oxynitride of molybdenum, or a layer containing an oxide oran oxynitride of a mixture of tungsten and molybdenum may be formed.Note that the mixture of tungsten and molybdenum corresponds to an alloyof tungsten and molybdenum, for example.

In the case where the separation layer is formed to have a stacked-layerstructure including a layer containing tungsten and a layer containingan oxide of tungsten, the layer containing an oxide of tungsten may beformed as follows: the layer containing tungsten is formed first and aninsulating film formed of an oxide is formed thereover, so that thelayer containing an oxide of tungsten is formed at the interface betweenthe tungsten layer and the insulating film. Alternatively, the layercontaining an oxide of tungsten may be formed by performing thermaloxidation treatment, oxygen plasma treatment, nitrous oxide (N₂O) plasmatreatment, treatment with a highly oxidizing solution such as ozonewater, or the like on the surface of the layer containing tungsten.Plasma treatment or heat treatment may be performed in an atmosphere ofoxygen, nitrogen, or nitrous oxide alone, or a mixed gas of any of thesegasses and another gas. Surface condition of the separation layer ischanged by the plasma treatment or heat treatment, whereby adhesionbetween the separation layer and the insulating layer formed later canbe controlled.

Each of the insulating layers can be formed by a sputtering method, aplasma CVD method, a coating method, a printing method, or the like. Forexample, the insulating layer is formed at a temperature of higher thanor equal to 250° C. and lower than or equal to 400° C. by a plasma CVDmethod, whereby the insulating layer can be a dense film with very lowwater permeability.

Then, a material for the sealing layer 213 is applied to a surface ofthe formation substrate 305 over which the coloring layer 259 and thelike are formed or a surface of the formation substrate 301 over whichthe light-emitting element 230 and the like are formed, and theformation substrate 301 and the formation substrate 305 are attached sothat these two surfaces face each other with the sealing layer 213positioned therebetween (FIG. 11C).

Next, the formation substrate 301 is separated, and the exposedinsulating layer 205 and the substrate 201 are attached to each otherwith the bonding layer 203. Further, the formation substrate 305 isseparated, and the exposed insulating layer 255 and the substrate 103are attached to each other with the bonding layer 105. Although thesubstrate 103 does not overlap with the conductive layer 157 in FIG.12A, the substrate 103 may overlap with the conductive layer 157.

Any of a variety of methods can be used as appropriate for theseparation process. For example, when a layer including a metal oxidefilm is formed as the separation layer on the side in contact with thelayer to be separated, the metal oxide film is embrittled bycrystallization, whereby the layer to be separated can be separated fromthe formation substrate. Alternatively, when an amorphous silicon filmcontaining hydrogen is formed as the separation layer between theformation substrate having high heat resistance and the layer to beseparated, the amorphous silicon film is removed by laser lightirradiation or etching, whereby the layer to be separated can beseparated from the formation substrate. Alternatively, after a layerincluding a metal oxide film is formed as the separation layer on theside in contact with the layer to be separated, the metal oxide film isembrittled by crystallization, and part of the separation layer isremoved by etching using a solution or a fluoride gas such as NF₃, BrF₃,or ClF₃, whereby the separation can be performed at the embrittled metaloxide film. Furthermore, a method may be used in which a film containingnitrogen, oxygen, hydrogen, or the like (for example, an amorphoussilicon film containing hydrogen, an alloy film containing hydrogen, analloy film containing oxygen, or the like) is used as the separationlayer, and the separation layer is irradiated with laser light torelease the nitrogen, oxygen, or hydrogen contained in the separationlayer as a gas, thereby promoting separation between the layer to beseparated and the formation substrate. Alternatively, it is possible touse a method in which the formation substrate provided with the layer tobe separated is removed mechanically or by etching using a solution or afluoride gas such as NF₃, BrF₃, or ClF₃, or the like. In this case, theseparation layer is not necessarily provided.

Further, the separation process can be conducted easily by combinationof the above-described separation methods. In other words, separationcan be performed with physical force (by a machine or the like) afterperforming laser light irradiation, etching on the separation layer witha gas, a solution, or the like, or mechanical removal with a sharpknife, scalpel or the like so that the separation layer and the layer tobe separated can be easily separated from each other.

Separation of the layer to be separated from the formation substrate maybe carried out by filling the interface between the separation layer andthe layer to be separated with a liquid. Further, the separation may beconducted while pouring a liquid such as water.

As another separation method, in the case where the separation layer isformed using tungsten, it is preferable that the separation be performedwhile etching the separation layer using a mixed solution of ammoniumwater and a hydrogen peroxide solution.

Note that the separation layer is not necessary in the case whereseparation at the interface between the formation substrate and thelayer to be separated is possible. For example, glass is used as theformation substrate, an organic resin such as polyimide, polyester,polyolefin, polyamide, polycarbonate, or acrylic is formed in contactwith the glass, and an insulating film, a transistor, and the like areformed over the organic resin. In this case, heating the organic resinenables the separation at the interface between the formation substrateand the organic resin. Alternatively, separation at the interfacebetween a metal layer and the organic resin may be performed in thefollowing manner: the metal layer is provided between the formationsubstrate and the organic resin and current is made to flow in the metallayer so that the metal layer is heated. The organic resin separatedfrom the formation substrate can be used as a substrate of thelight-emitting panel. Alternatively, the organic resin may be attachedto a substrate with an adhesive.

Lastly, an opening is formed in the insulating layer 255 and the sealinglayer 213 to expose the conductive layer 157 (FIG. 12B). In the casewhere the substrate 103 overlaps with the conductive layer 157, theopening is formed also in the substrate 103 and the bonding layer 105 sothat the conductive layer 157 is exposed (FIG. 12C). The method forforming the opening is not particularly limited and may be, for example,a laser ablation method, an etching method, an ion beam sputteringmethod, or the like. As another method, a cut may be made in a film overthe conductive layer 157 with a sharp knife or the like and part of thefilm may be separated by physical force.

In the above-described manner, the light-emitting panel can bemanufactured.

As described above, the light-emitting panel of this embodiment includestwo substrates; one is the substrate 103 and the other is the substrate201 or the substrate 202. The light-emitting panel can be formed withtwo substrates even when including a touch sensor. Owing to the use ofthe minimum number of substrates, improvement in light extractionefficiency and improvement in clarity of display can be easily achieved.

This embodiment can be combined with any other embodiment asappropriate.

Embodiment 3

In this embodiment, a light-emitting panel will be described withreference to FIG. 13.

The light-emitting panel shown in FIG. 13 includes a substrate 401, thetransistor 240, the light-emitting element 230, the insulating layer207, the insulating layer 209, the insulating layer 211, the insulatinglayer 217, a space 405, the insulating layer 261, the light-blockinglayer 257, the coloring layer 259, a light-receiving element (includingthe p-type semiconductor layer 271, the i-type semiconductor layer 273,and the n-type semiconductor layer 275), the conductive layer 281, theconductive layer 283, the insulating layer 291, the insulating layer293, the insulating layer 295, and a substrate 403.

The light-emitting panel includes a bonding layer (not shown) formed ina frame shape between the substrate 401 and the substrate 403 tosurround the light-emitting element 230 and the light-receiving element.The light-emitting element 230 is sealed by the bonding layer, thesubstrate 401, and the substrate 403.

In the light-emitting panel of this embodiment, the substrate 403 has alight-transmitting property. Light emitted from the light-emittingelement 230 is extracted to the air through the coloring layer 259, thesubstrate 403, and the like.

The light-emitting panel of this embodiment is capable of touchoperation. Specifically, proximity or contact of an object on a surfaceof the substrate 403 can be sensed with the light-receiving element.

An optical touch sensor is highly durable and preferable because itssensing accuracy is not affected by damage to a surface that is touchedby an object. An optical touch sensor is also advantageous in that it iscapable of noncontact sensing, it does not degrade the clarity of imageswhen used in a display device, and it is applicable to large-sizedlight-emitting panels and display devices.

It is preferable to provide an optical touch sensor between thesubstrate 403 and the space 405 because the optical touch sensor is lesslikely to be affected by light emitted from the light-emitting element230 and can have improved S/N ratio.

The light-blocking layer 257 is closer to the substrate 401 than is thelight-receiving element and overlaps with the light-receiving element.The light-blocking layer 257 can prevent the light-receiving elementfrom being irradiated with light emitted from the light-emitting element230.

There is no particular limitation on materials used for the substrates401 and 403. The substrate through which light emitted from thelight-emitting element is extracted is formed using a material thattransmits the light. For example, a material such as glass, quartz,ceramics, sapphire, or an organic resin can be used. Since the substratethrough which light is not extracted does not need a light-transmittingproperty, a metal substrate or the like using a metal material or analloy material can be used as well as the above-mentioned substrates.Further, any of the materials for the substrates given in the aboveembodiments can also be used for the substrates 401 and 403.

A method for sealing the light-emitting panel is not limited, and eithersolid sealing or hollow sealing can be employed. For example, as asealing material, a glass material such as a glass frit, or a resinmaterial such as a resin that is curable at room temperature (e.g., atwo-component-mixture-type resin), a light curable resin, or athermosetting resin can be used. The space 405 may be filled with aninert gas such as nitrogen or argon, or with a resin or the like similarto that used for the sealing layer 213. Further, the resin may includethe drying agent, the filler with a high refractive index, or thescattering member.

This embodiment can be combined with any other embodiment asappropriate.

Example

In this example, a light-emitting device of one embodiment of thepresent invention was fabricated. The light-emitting device of thisexample can be called a tri-fold folding screen type display.

FIGS. 18A and 18B illustrate a light-emitting panel of thelight-emitting device fabricated in this example. The light-emittingdevice fabricated in this example differs from Specific Example 1 (FIG.7B) described in Embodiment 2 in that the substrate 103 and thesubstrate 201 have different sizes and in that the insulating layer 217is provided between pixels of different colors. For other components,description of Specific Example 1 and the like can be referred to. Forthe insulating layer 217, description of Specific Example 2 and the likecan be referred to.

The light-emitting panel was fabricated by using the fabrication methoddescribed in Embodiment 2.

First, the separation layer 303 was formed over a glass substrateserving as the formation substrate 301, and a layer to be separated wasformed over the separation layer 303. In addition, the separation layer307 was formed over a glass substrate serving as the formation substrate305, and a layer to be separated was formed over the separation layer307. Next, the formation substrate 301 and the formation substrate 305were attached so that the surfaces on which the layers to be separatedwere formed faced each other. Then, the two formation substrates wereseparated from the layers to be separated, and flexible substrates wereattached to the layers to be separated. Materials for each of the layersare described below.

A stacked-layer structure of a tungsten film and a tungsten oxide filmover the tungsten film was formed as each of the separation layers 303and 307.

The stacked-layer structure of the separation layer right afterdeposition is not easily separated; however, by reaction with aninorganic insulating film by heat treatment, the state of the interfacebetween the separation layer and the inorganic insulating film ischanged to become brittle. Then, forming a starting point of separationenables physical separation.

As the layer to be separated over the separation layer 303, theinsulating layer 205, a transistor, and an organic EL element serving asthe light-emitting element 230 were formed. As the layer to be separatedover the separation layer 307, the insulating layer 255, a color filter(corresponding to the coloring layer 259), and the like were formed.

A stacked-layer structure including a silicon oxynitride film, a siliconnitride film, and the like was used as each of the insulating layers 205and 255.

As the transistor, a transistor including a c-axis aligned crystallineoxide semiconductor (CAAC-OS) was used. Since the CAAC-OS, which is notamorphous, has few defect states, using the CAAC-OS can improve thereliability of the transistor. Moreover, since the CAAC-OS does not havea grain boundary, stress that is caused by bending a flexible devicedoes not easily make a crack in a CAAC-OS film.

A CAAC-OS is an oxide semiconductor having c-axis alignment in adirection substantially perpendicular to the film surface. It has beenfound that oxide semiconductors have a variety of crystal structuresother than an amorphous structure and a single-crystal structure. Anexample of such structures is a nano-crystal (nc) structure, which is anaggregate of nanoscale microcrystals. The crystallinity of a CAACstructure is lower than that of a single-crystal structure but higherthan those of an amorphous structure and an nc structure.

In this example, a channel-etched transistor including an In—Ga—Zn-basedoxide was used. The transistor can be fabricated over a glass substrateat a process temperature lower than 500° C.

In a method of fabricating an element such as a transistor directly overan organic resin such as a plastic substrate, the temperature of theprocess for fabricating the element needs to be lower than the uppertemperature limit of the organic resin. In this example, the formationsubstrate is a glass substrate and the separation layer, which is aninorganic film, has high heat resistance; accordingly, the transistorcan be fabricated at a temperature equal to that when a transistor isfabricated over a glass substrate. Thus, the performance and reliabilityof the transistor can be easily secured.

As the light-emitting element 230, a tandem organic EL element thatincludes a fluorescence-emitting unit including a blue light-emittinglayer and a phosphorescence-emitting unit including a greenlight-emitting layer and a red light-emitting layer was used. Thelight-emitting element 230 has a top emission structure. As the lowerelectrode 231 of the light-emitting element 230, an aluminum film, atitanium film over the aluminum film, and an ITO film serving as anoptical adjustment layer over the titanium film were stacked. Thethickness of the optical adjustment layer was varied depending on thecolor of the pixel. Owing to the combination of a color filter and amicrocavity structure, light with high color purity can be extractedfrom the light-emitting panel fabricated in this example. As each of thesubstrates 103 and 201, a 20-μm-thick flexible organic resin film wasused.

The fabricated light-emitting panel had a size of a light-emittingportion (pixel portion) of 5.9 inches diagonal, 720×1280×3 (RGB) pixels,a pixel pitch of 0.102 mm×0.102 mm, a resolution of 249 ppi, and anaperture ratio of 45.2%. A built-in scan driver and an external sourcedriver attached by chip on film (COF) were used.

FIGS. 19A to 19D are photographs showing the display on thelight-emitting device fabricated in this example. FIG. 19A shows thelight-emitting device that is opened, FIGS. 19B and 19C each show thelight-emitting device that is being folded, and FIG. 19D shows thelight-emitting device that is folded. The curvature radius of a foldedportion was 4 mm. The light-emitting device of this example had noproblem in display and driving even when it was folded while displayingan image. The light-emitting device of this example has a function ofsensing whether it is in an opened state or in a folded state with asensor and displaying different images depending on the state. Owing tothis function, the light-emitting device also has a function of savingpower by stopping the driving of a region of the light-emitting panelthat is hidden in a folded state.

Here, if the light-emitting panel is completely fixed with a pair ofprotective layers and/or a pair of support panels, when thelight-emitting device is folded, the light-emitting panel is undertension to be broken in some cases. In addition, when the light-emittingdevice is opened, the light-emitting panel is under force in a directionto cause contraction of the light-emitting panel to be broken in somecases. The light-emitting panel of the light-emitting device fabricatedin this example is not completely fixed with a pair of protective layersand/or a pair of support panels. Accordingly, when the light-emittingdevice is folded or opened, the light-emitting panel slides so that theposition of the light-emitting panel with respect to the pair ofprotective layers and/or the pair of support panels changes. Thus, thelight-emitting panel can be prevented from being broken by being underforce.

FIGS. 20A to 20C illustrate a light-emitting device of one embodiment ofthe present invention. Here, the light-emitting panel 11 is not fixedwith a pair of support panels 15 a(1) and 15 b(1). The light-emittingpanel 11 is supported with a pair of support panels 15 a(2) and 15 b(2),a pair of support panels 15 a(3) and 15 b(3), or both of these pairs.Although the light-emitting device of one embodiment of the presentinvention includes a plurality of pairs of support panels, thelight-emitting panel only needs to be fixed with at least one pair ofsupport panels.

The display on the light-emitting panel 11 along dashed-dotted lineM1-N1 in the light-emitting device in an opened state shown in FIG. 20Ais along dashed-dotted line M2-N2 in the light-emitting device that isbeing folded, shown in FIG. 20B. Furthermore, the display is alongdashed-dotted line M3-N3 in the light-emitting device in a folded stateshown in FIG. 20C. In this manner, in the light-emitting device of oneembodiment of the present invention, the light-emitting panel slideswhen the light-emitting device is folded or opened because thelight-emitting panel is not completely fixed with a pair of protectivelayers and/or a pair of support panels. Accordingly, the position of thelight-emitting panel with respect to the pair of protective layersand/or the pair of support panels changes. Thus, the light-emittingpanel can be prevented from being broken by being under force.

EXPLANATION OF REFERENCE

-   11: light-emitting panel, 11 a: light-emitting region, 11 b:    non-light-emitting region, 13: protective layer, 13 a: protective    layer, 13 b: protective layer, 15: support panel, 15 a: support    panel, 15 b: support panel, 101: element layer, 103: substrate, 104:    light extraction portion, 105: bonding layer, 106: driver circuit    portion, 108: FPC, 108 a: FPC, 108 b: FPC, 156: conductive layer,    157: conductive layer, 201: substrate, 202: substrate, 203: bonding    layer, 205: insulating layer, 207: insulating layer, 208: conductive    layer, 209: insulating layer, 209 a: insulating layer, 209 b:    insulating layer, 211: insulating layer, 212: conductive layer, 213:    sealing layer, 215: connector, 215 a: connector, 215 b: connector,    217: insulating layer, 230: light-emitting element, 231: lower    electrode, 233: EL layer, 235: upper electrode, 240: transistor,    255: insulating layer, 257: light-blocking layer, 259: coloring    layer, 261: insulating layer, 270: conductive layer, 271: p-type    semiconductor layer, 272: conductive layer, 273: i-type    semiconductor layer, 274: conductive layer, 275: n-type    semiconductor layer, 276: insulating layer, 278: insulating layer,    280: conductive layer, 281: conductive layer, 283: conductive layer,    291: insulating layer, 292: conductive particles, 293: insulating    layer, 294: conductive layer, 295: insulating layer, 296: conductive    layer, 301: formation substrate, 303: separation layer, 305:    formation substrate, 307: separation layer, 310 a: conductive layer,    310 b: conductive layer, 401: substrate, 403: substrate, 405: space.

This application is based on Japanese Patent Application serial No.2013-146291 filed with Japan Patent Office on Jul. 12, 2013, JapanesePatent Application serial No. 2013-146293 filed with Japan Patent Officeon Jul. 12, 2013, and Japanese Patent Application serial No. 2013-249155filed with Japan Patent Office on Dec. 2, 2013, the entire contents ofwhich are hereby incorporated by reference.

The invention claimed is:
 1. A light-emitting device comprising: aflexible light-emitting panel; a first support panel; and a secondsupport panel, wherein the flexible light-emitting panel comprises aregion capable of being bent outward so that a gap of the flexiblelight-emitting panel decreases as a distance from the region increases,wherein the region is located between the first support panel and thesecond support panel, wherein the region is capable of displaying animage in a state where the flexible light-emitting panel is folded, andwherein each of the first support panel and the second support panel hasa lower flexibility than a flexibility of the flexible light-emittingpanel.
 2. The light-emitting device according to claim 1, wherein theflexible light-emitting panel comprises an electroluminescence element.3. A light-emitting device comprising: a flexible light-emitting panel;a first support panel; and a second support panel, wherein the flexiblelight-emitting panel comprises a region capable of being bent outwardwith a curvature radius and a first flat region and a second flat regioneach connected to the region so that a distance between the first flatregion and the second flat region is less than twice the curvatureradius, wherein the region is located between the first support paneland the second support panel, wherein the region is capable ofdisplaying an image in a state where the flexible light-emitting panelis folded, and wherein each of the first support panel and the secondsupport panel has a lower flexibility than a flexibility of the flexiblelight-emitting panel.
 4. The light-emitting device according to claim 3,wherein the flexible light-emitting panel comprises anelectroluminescence element.
 5. A light-emitting device comprising: aflexible light-emitting panel; a first support panel; and a secondsupport panel, wherein the flexible light-emitting panel comprises aregion capable of being bent outward with a curvature radius so that agap of the flexible light-emitting panel decreases as a distance fromthe region increases, wherein the region is located between the firstsupport panel and the second support panel, wherein the region iscapable of displaying an image in a state where the flexiblelight-emitting panel is folded, wherein each of the first support paneland the second support panel has a lower flexibility than a flexibilityof the flexible light-emitting panel, and wherein the curvature radiusis greater than or equal to 1 mm and less than or equal to 150 mm. 6.The light-emitting device according to claim 5, wherein the flexiblelight-emitting panel comprises an electroluminescence element.
 7. Alight-emitting device comprising: a flexible light-emitting panel; afirst support panel; and a second support panel, wherein the flexiblelight-emitting panel comprises a region capable of being bent outwardwith a curvature radius and a first flat region and a second flat regioneach connected to the region so that a distance between the first flatregion and the second flat region is less than twice the curvatureradius, wherein the region is located between the first support paneland the second support panel, wherein the region is capable ofdisplaying an image in a state where the flexible light-emitting panelis folded, wherein each of the first support panel and the secondsupport panel has a lower flexibility than a flexibility of the flexiblelight-emitting panel, and wherein the curvature radius is greater thanor equal to 1 mm and less than or equal to 150 mm.
 8. The light-emittingdevice according to claim 7, wherein the flexible light-emitting panelcomprises an electroluminescence element.